Bendamustine is used in the treatment of a number of cancers including leukemias, Hodgkin's disease and multiple myelomas. Bendamustine (present as the HCl salt) is the active ingredient of the commercial product Treanda™, a lyophilized powder for reconstitution. Current labeling requirements call for the reconstituted product to be immediately (within 30 minutes) diluted into 500 mL of parenterally acceptable diluents such as 0.9% saline (normal saline) or 2.5% dextrose/0.45% saline and administered as part of an intravenous infusion delivering 100 mg/m2 over 30 minutes or 120 mg/m2 over 60 minutes. The diluted admixture may be stored at 2-8° C. for up to 24 hours, or 3 hours at room temperature (15-30° C.); administration must be completed within this period due to limited chemical stability in aqueous solutions.
Solubility limitations at 2-8° C. with currently approved and/or available formulations are believed to prevent current formulations from being administered in smaller more concentrated infusion volumes up to about 150 ml; at volumes below 150 ml, solubility is not sufficient even at 25° C. Side effects associated with extravasation and local erythema, swelling and pain at the injection site also dictate that the infusion be as dilute as possible. Therefore, precautions are taken to avoid extravasation, including monitoring of the intravenous infusion site for redness, swelling, pain, infection, and necrosis during and after administration of bendamustine. Higher infusion volume and longer infusion times, however, are associated with many drawbacks. For example, after reconstitution, the current product has a short period of stability, degradation of the drug occurs from the time of reconstitution until the entire large volume infusion has been completely administered. The current label for Treanda™ therefore instructs that the admixture should be prepared as close as possible to the time of patient administration, and that administration of Treanda™ must be completed within the durations indicated above. From patient comfort and nursing administration points of view, higher infusion volumes and long infusion times are undesirable. Higher infusion volumes may be associated with higher likelihood of weight gain and edema. Shorter infusion times and smaller infusion volumes result in a better quality of life experience for the patient by reducing the overall “stress” to the patient and reducing the time spent in the infusion clinic. Shorter infusion times (and smaller volumes) also reduce the potential extravasation (and shorten the patient monitoring time required). It would be advantageous if the drug could be administered in smaller volumes and over shorter times. The present invention addresses these needs.